1. Field of the Invention
The present invention relates to image forming apparatuses, and more particularly, to an image forming apparatus receiving reflected light from an illuminated original for obtaining image data.
2. Description of the Related Art
Because an apparatus that reads out an original electrically has random noise superimposed on the readout data, only data of low reliability can be obtained with just one readout operation. An apparatus is known that reads out an image of the same original simultaneously by two CCDs, whereby an average of the readout two image data is adapted as the true image data.
If image data obtained by scanning a book or a cut-and-pasted original is directly output as a hard copy, the frame of the book or the edges of the cut-and-pasted original will appear as shadow regions in the image. It is necessary to eliminate image data of such shadow region to obtain a satisfactory image.
A device erasing such shadow region data is well known as follows. Edge data of a shadow region in a specified region is detected and determination is made that all the area between the edge data is a shadow region, whereby that region is completely erased.
In the above-described first conventional case, random noise can be removed to a certain level, but the picture quality of the image is not satisfactory since there is only one light source that illuminates the original.
In the above-described second conventional case, the usability is not satisfactory since it merely detects a shadow region in a specified area.